TABLE 3.
Effects of antibiotics on survival
| Addition (concn) |
N/N0 fora:
|
|
|---|---|---|
| dnaE+ strain | dnaE74 strain | |
| None | 256b | 0.0069b |
| Chloramphenicol (20 μg/ml) | 0.85 | 1.06 |
| Rifampin (50 μg/ml) | 0.49 | 0.92 |
| Tetracycline (15 μg/ml) | 1.13 | 0.89 |
| Hydroxyurea (40 mM)c | 1.6 × 10−4 | 9.1 × 10−6 |
a
N, viable count at 5 h; N0, viable count at zero time. Overnight cultures in LB medium (dnaE+ strain, ∼6 × 109 cells/ml; dnaE strain, ∼7 × 109 cells/ml) were diluted 1:1,000 in 10 ml of LB medium, and the cultures were supplemented with antibiotics and incubated with shaking for 5 h at 40°C. At the end of the experiment the cultures were diluted and plated on LB medium plates.
b
Average of three determinations.
c
Data also shown in Table 9.